What Happened to IPv5?

IP Version 5 (IPv5) was a IP-layer protocol that provides end-to-end guaranteed service across a network. That is, it was compatible with IP at the network layer but was built to provide a Quality of Service for streaming services.The Quality of Service looks very similar to Resource Reservation Protocol (RSVP) in that state was maintained in every router in the network.RFC1190 defines it as the following (Note: ST is the name used for Internet Stream Protocol and assigned IPv5 sometime later).

The version of Internet Protocol (IP) used on most computer networks today is four, typically called IPv4. The next version of IP expected to one day become the new worldwide standard is version six (IPv6). Some people who study computer networking are understandably curious to know what happened to the protocol version in-between, the hypothetical IPv5.

In short, IPv5 never became an official protocol. Many years ago, Internet Stream Protocol (ST)was considered IP version five by industry researchers, but ST was abandoned before ever becoming a standard or widely known as IPv5. Work on ST and IPv5 is not expected to ever restart.

IPv4 (Internet Protocol Version4)

IPV4 is divided into classes of addresses. Each class has unique properties:

Class A. First octet ranges from 1 through 126. <127 is a reserved address>

Class B. First octet ranges from 128 through 191.

Class C. First octet ranges from 192 through 223.

If we take a look at the first octet of 192.168.1.1; We can see that 192 fits into the Class C category. To find out in which category our IP address belongs to we should always look at the first octet. What do those octets in the IP address mean and does it really matter what class they belong to? Well, yes, it does matter what class they belong to. The Octets in the different classes identify either the Network portion or the Host portion of the address.

N = Network, H = Host
Class A. N.H.H.H
Class B. N.N.H.H
Class C. N.N.N.H

Breaking down an IP address:
Let’s open up our command prompt and ping www.yahoo.com.The IP address I got at the time of this ping is 68.142.226.41. What class does this IP address fit into? If you guessed Class A you are right. By taking a look at the first octet which is 68 we can see that it fits into the Class A category. We can break it down like this:
68.142.226.41:

68. = N (network part of the IP) 8 bits in the network portion
142. = H (host part of the IP) 8 bits in the host portion
226. = H (host part) 8 bits in the host portion
41 = H (host part) 8 bits in the host portion

4 x 8 = 32 bits total. Four octets times eight is always 32 bits.

Typically it is much easier to use a Class C type because you would only need to change the Host portion of the IP address which would only be one in Class C. For example if our gateway or the main IP for the router is 192.168.1.1, all the IPs in that network should all have the same first three octets which are 192.168.1.0. All the computers can then be given a different IP like 192.168.1.50, 192.168.1.51 and so on by just changing the last octet and keeping the first three. In a class B you would have to keep the first two and change the last two. With a class A you would keep the first and change the last three octets. So in Yahoo’s IP, the first octet (68) is the Network portion of the IP. So 142.226.41 are the host portion of that one computer you pinged. As you can see it can get quite complex for very large networks. 
Earlier in this essay/tutorial I mentioned routers love binary. How can we turn all of these numbers into binary? Binary is all 0’s and 1’s. It is very simple. Take out a sheet a paper and from Right to Left write down a number 1. Now double that 1 and next to it (on the left) right a 2. Now double that 2. Next to that 2 write down a 4. Double that 4 and so on until you reach 128. It should look like this:

Formula: 128 64 32 16 8 4 2 1

If you add these 8 numbers you are going to get 255. To get the binary of an IP address you will have to take out each IP address and calculate it. You must take the first octet and try to calculate what numbers from the formula add up to the first octet and so on. If the first octet is 10 you would put a 1 under 8 and a 1 under 2. 8+2 equals 10. Then all you have to do is put a 0 under the rest of the formula numbers. Do it like this:

128 64 32 16 8 4 2 1 = 255
________________________________________________
192.| 1 1 0 0 0 0 0 0
168.| 1 0 1 0 1 0 0 0 128+32+8=168
1. | 0 0 0 0 0 0 0 1 1=1
1 | 0 0 0 0 0 0 0 1 1=1


So now if we take all of those zeros and ones we get this: 
11000000 10101000 00000001 00000001. Awesome now we know how to convert these IP addresses into binary. But lets keep this in mind for right now. 1+1 = 1, 1+0 = 0, and 0+1 = 0. Yeah that’s right, 1 plus 1 is 1 and 0 plus 1 is zero.

All networks have a default mask (wont get much into that, you can simply google network mask, or default mask):

Class A’s default mask: 255.0.0.0
Class B’s default mask: 255.255.0.0
Class C’s default mask: 255.255.255.0

(To get the binary numbers for these masks is so easy. If the number is 255 all we have to do is right down eight 1’s. (11111111 = 255). If it is a zero we write down eight 0’s (00000000 = 0)). 
So to get the default mask of your of your computers IP address all you have to do is calculate your IP address into binary. Then you calculate the default mask into binary. Remember now, you must look at the first octet of your IP address and find out in what category it fits into. If it is a class B then your default mask would be 255.255.0.0. (that in binary would be: 11111111 11111111 00000000 00000000). 

Earlier I mentioned that 1 + 1 equals 1 and 0 + 1 or 1 +0 equals 0. This is the binary formula for calculating your default mask into binary, that’s what your router will be using to send and receive, all zero’s and one’s. We have already calculate 192.168.1.1 and we got 11000000 10101000 00000001 00000001 when we calculated it into binary. So lets take this number and add it too the default masks’s binary number. In our case the 192 falls into the Class C so the default mask is 255.255.255.0 
( 11111111 11111111 11111111 00000000).
We add them like this (remember 1 + 1 equals 1 and 0 + 1 or 1 + 0 equals 0):
192.168.1.1 = 11000000 10101000 00000001 00000001

255.255.255.0 = 11111111 11111111 11111111 00000000
__________________________________
Default mask = 11000000 10101000 00000001 00000001

So the default mask of 192.168.1.1 in binary is 11000000 10101000 00000001 00000001, the funny part is that the number you get should equal the 192.168.1.1 in binary. How many bits are there in the network portion of 192.168.1.1? Three times eight is 24. There are 24 bits in the network portion of the 192.168.1.1. If you don’t know how I got that re-read this tutorial.

LTE Channels

LTE physical channels

The LTE physical channels vary between the uplink and the downlink as each has different requirements and operates in a different manner.

Downlink:

Physical Broadcast Channel (PBCH):   This physical channel carries system information for UEs requiring to access the network. It only carries what is termed Master Information Block, MIB, messages. The modulation scheme is always QPSK and the information bits are coded and rate matched - the bits are then scrambled using a scrambling sequence specific to the cell to prevent confusion with data from other cells.

The MIB message on the PBCH is mapped onto the central 72 subcarriers or six central resource blocks regardless of the overall system bandwidth. A PBCH message is repeated every 40 ms, i.e. one TTI of PBCH includes four radio frames.

The PBCH transmissions has 14 information bits, 10 spare bits, and 16 CRC bits.

Physical Control Format Indicator Channel (PCFICH) :   As the name implies the PCFICH informs the UE about the format of the signal being received. It indicates the number of OFDM symbols used for the PDCCHs, whether 1, 2, or 3. The information within the PCFICH is essential because the UE does not have prior information about the size of the control region.

A PCFICH is transmitted on the first symbol of every sub-frame and carries a Control Format Indicator, CFI, field. The CFI contains a 32 bit code word that represents 1, 2, or 3. CFI 4 is reserved for possible future use.

The PCFICH uses 32,2 block coding which results in a 1/16 coding rate, and it always uses QPSK modulation to ensure robust reception.

Physical Downlink Control Channel (PDCCH) :   The main purpose of this physical channel is to carry mainly scheduling information of different types:

• Downlink resource scheduling
• Uplink power control instructions
• Uplink resource grant
• Indication for paging or system information

The PDCCH contains a message known as the Downlink Control Information, DCI which carries the control information for a particular UE or group of UEs. The DCI format has several different types which are defined with different sizes. The different format types include: Type 0, 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, 3, 3A, and 4.

Physical Hybrid ARQ Indicator Channel (PHICH) :   As the name implies, this channel is used to report the Hybrid ARQ status. It carries the HARQ ACK/NACK signal indicating whether a transport block has been correctly received. The HARQ indicator is 1 bit long - "0" indicates ACK, and "1" indicates NACK.

The PHICH is transmitted within the control region of the subframe and is typically only transmitted within the first symbol. If the radio link is poor, then the PHICH is extended to a number symbols for robustness.

• Uplink:

Physical Uplink Control Channel (PUCCH) :   The Physical Uplink Control Channel, PUCCH provides the various control signalling requirements. There are a number of different PUCCH formats defined to enable the channel to carry the required information in the most efficient format for the particular scenario encountered. It includes the ability to carry SRs, Scheduling Requests.

The basic formats are summarised below:

PUCCH FORMAT	UPLINK CONTROL INFORMATION	MODULATION SCHEME	BITS PER SUB-FRAME	NOTES
Format 1	SR	N/A	N/A
Format 1a	1 bit HARQ ACK/NACK with or without SR	BPSK	1
Format 1b	2 bit HARQ ACK/NACK with or without SR	QPSK	2
Format 2	CQI/PMI or RI	QPSK	20
Format 2a	CQI/PMI or RI and 1 bit HARQ ACK/NACK	QPSK + BPSK	21
Format 2b	CQI/PMI or RI and 2 bit HARQ ACK/NACK	QPSK + BPSK	22
Format 3				Provides support for carrier aggregation.

Physical Uplink Shared Channel (PUSCH) :   This physical channel found on the LTE uplink is the Uplink counterpart of PDSCH

Physical Random Access Channel (PRACH) :   This uplink physical channel is used for random access functions. This is the only non-synchronised transmission that the UE can make within LTE. The downlink and uplink propagation delays are unknown when PRACH is used and therefore it cannot be synchronised.

The PRACH instance is made up from two sequences: a cyclic prefix and a guard period. The preamble sequence may be repeated to enable the eNodeB to decode the preamble when link conditions are poor.

LTE transport channels

The LTE transport channels vary between the uplink and the downlink as each has different requirements and operates in a different manner. Physical layer transport channels offer information transfer to medium access control (MAC) and higher layers.

Downlink:

Broadcast Channel (BCH) :   The LTE transport channel maps to Broadcast Control Channel (BCCH)

Downlink Shared Channel (DL-SCH) :   This transport channel is the main channel for downlink data transfer. It is used by many logical channels.

Paging Channel (PCH) :   To convey the PCCH

Multicast Channel (MCH) :   This transport channel is used to transmit MCCH information to set up multicast transmissions.

Uplink:

Uplink Shared Channel (UL-SCH) :   This transport channel is the main channel for uplink data transfer. It is used by many logical channels.

Random Access Channel (RACH) :   This is used for random access requirements.

LTE logical channels

The logical channels cover the data carried over the radio interface. The Service Access Point, SAP between MAC sublayer and the RLC sublayer provides the logical channel.

Control channels: these LTE control channels carry the control plane information:

Broadcast Control Channel (BCCH) :   This control channel provides system information to all mobile terminals connected to the eNodeB.

Paging Control Channel (PCCH) :   This control channel is used for paging information when searching a unit on a network.

Common Control Channel (CCCH) :   This channel is used for random access information, e.g. for actions including setting up a connection.

Multicast Control Channel (MCCH) :   This control channel is used for Information needed for multicast reception.

Dedicated Control Channel (DCCH) :   This control channel is used for carrying user-specific control information, e.g. for controlling actions including power control, handover, etc..

Traffic channels:These LTE traffic channels carry the user-plane data:

Dedicated Traffic Channel (DTCH) :   This traffic channel is used for the transmission of user data.

Multicast Traffic Channel (MTCH) :   This channel is used for the transmission of multicast data.